In the following we briefly analyze and compare voice of the different races of Black-backed Grosbeak (Pheucticus aureoventris). We also try to quantify the extent of any vocal differences using the criteria proposed by Tobias et al. (2010), as a support for taxonomic review. We have made use of sound recordings available on-line from Xeno Canto (XC) and Macaulay Library (ML).
Our main interest is to compare yellow-throated race crissalis with all other (black-throated) races. An overview of song (illustrated with multiple sonograms in the pdf version of this note): crissalis (n=4), southern races (Peru, Bolivia, Argentina), northern race (Colombia).
Song of all races is rather similar. crissalis seems to differ however in having very short song phrases of just a few notes (1-4 notes, duration 0.5-2s). Other races typically have somewhat longer song phrases with more notes (2-10 notes, duration 0.7 - 3s). Based on phrase length and number of notes, a total vocal score 1 + 1 = 2 could be given.
This note was finalized on 29th June 2016, using sound recordings available on-line at that moment. We would like to thank in particular the sound recordists who placed their recordings for this species on XC, ML: Roger Ahlman, Michael Anderson, Juan Areta, Nick Athanas, Peter Boesman, Paul Coopmans, Pablo Florez, José Giraldo, Mateo Hernandez, Niels Krabbe, Dan Lane, Bernabe Lopez-Lanus, Sjoerd Mayer, John V Moore, Gabriel Leite, Ted Parker, Mark Robbins, Fabrice Schmitt, Thomas Schulenberg, Glenn Seeholzer and Andrew Spencer.
Tobias, J.A., Seddon, N., Spottiswoode, C.N., Pilgrim, J.D., Fishpool, L.D.C. & Collar, N.J. (2010). Quantitative criteria for species delimitation. Ibis 152(4): 724–746.
More Information: on383_black-backed_grosbeak.pdf